According to the latest report, a minibus with a Moldovan license plate and carrying four passengers, citizens of Moldova, stopped on the Russian side of the border awaiting permission to enter Ukrainian territory.

Border guards examining the vehicle found another man hiding inside.

It has already been established that this person illegally passed through the Russian checkpoint on the two countries' border.

The suspect detonated an unknown explosive device at passport control.

"As a result of the explosion, officers of the [Ukrainian] State Border Guard Service were injured and were rushed to a hospital in the town of Hlukhiv last night. They are currently in serious condition," the spokesman said.